There are different types of spas and in every country in the world also always very specific rules that define exactly when a place is a resort town and thus suitable for a health holiday. Only if this municipality has been awarded a corresponding predicate, it may call itself a "resort town" or "spa town". Somewhat simplified one can say, a resort town exists mostly there, where the following 4 points come together:
- The occurrence of a natural remedy (e.g. natural thermal water or mineral therapeutic mud),
- A particularly health-promoting local climate (e.g. particularly pure air without exhaust fumes or a particularly salty sea breeze),
- Local spa businesses have developed special therapies for the treatment of conditions (e.g. spa hotels)
- In addition to the above points, there is a particularly relaxing environment (e.g. spa parks, architecture, nature or traffic-calmed city centers).